Package org.terrier.matching.models.normalisation

Class NormalisationJN

java.lang.Object

org.terrier.matching.models.normalisation.Normalisation

org.terrier.matching.models.normalisation.NormalisationJN

All Implemented Interfaces:

java.io.Serializable, java.lang.Cloneable

public class NormalisationJN
extends Normalisation

This class implements the tf normalisation based on Jelinek-Mercer smoothing for language modelling where collection model is given by document frequency instead of term frequency.

Author:

Ben He

See Also:

Serialized Form

Field Summary

Fields

Modifier and Type	Field	Description
protected java.lang.String	methodName	The name of the normalisation method .

Fields inherited from class org.terrier.matching.models.normalisation.Normalisation

averageDocumentLength, idf, Nt, numberOfDocuments, numberOfTokens, parameter, termFrequency

Constructor Summary

Constructors

Constructor	Description
NormalisationJN()

Method Summary

Modifier and Type	Method	Description
java.lang.String	getInfo()	Get the name of the normalisation method.
double	normalise(double tf, double docLength, double termFrequency)	This method gets the normalised term frequency.

Methods inherited from class org.terrier.matching.models.normalisation.Normalisation

clone, getParameter, setAverageDocumentLength, setDocumentFrequency, setNumberOfDocuments, setNumberOfTokens, setParameter

Methods inherited from class java.lang.Object

equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

methodName

protected final java.lang.String methodName

The name of the normalisation method .

See Also:

Constant Field Values

Constructor Detail

NormalisationJN

public NormalisationJN()

Method Detail

getInfo

public java.lang.String getInfo()

Get the name of the normalisation method.

Specified by:

getInfo in class Normalisation

Returns:

Return the name of the normalisation method.

normalise

public double normalise(double tf,
                        double docLength,
                        double termFrequency)

This method gets the normalised term frequency.

Specified by:

normalise in class Normalisation

Parameters:

tf - The frequency of the query term in the document.

docLength - The number of tokens in the document.

termFrequency - The frequency of the query term in the collection.

Returns:

The normalised term frequency.